@HollyBleu, yes, this issue for them was solved becasue a solution has been marked as Accepted Solution. 🙂 You can find it on the first page where Kreatora gives instructions how to fix if you problem is caused by Mods/CC like the Original Poster's was. Do you use Mods or Custom Content (CC). 🤔 If so, you can do what Kreatora suggests in the Accepted Answser. Or here is another version of what worked.
Please do all of the following:
1) Move the Mods Folder to your desktop
2) Delete localthumbcache.package file in the game folder.
3) Fix you game in Origin by logging in and go to Library, then right-click on The Sims 4 and choose the "Repair Game" option from the list. Wait until Origin finishes repairing all your packs and not just the base game.
4) Now, when you turn on your game again, it will create a new mods folder that will be empty. Check to see if your game is now working without mods/CC.
5) Now you can try adding back items from your Mods folder one at a time checking your game each time to see which item is causing your game to not work properly. If you have a lot of items, you can try the 50/50 Method.
The CC creators will usually update the CC items and Mods after these updates, so when you find out which one is the culprit, you can get the updated version from whoever made that item of CC in the first place. 🙂
If you use Mods/CC then it is best if you do these steps whenever you have a problem in your game , especially after EA updates/patches the game.
If these steps don't work or if you don't use Mods/CC then please update us!